Wartime does produce some amazing innovations... watching through the clip you do notice the snatch launch was for recovering gliders from the forward landing zones.
Luckily for the "Giant C-47 transports" so tasked, there were not too many gliders that actually survived any landing!
Reminds me of some of the first attempts at airborne refuelling - see the end of this clip
https://www.youtube.com/watch?v=-KS3j-zVKQ4